1. Field of the Invention
This invention relates to a connector for the connection of the outer end portion of a pipe, a pipe line, a pipe string or coiled tubing, the connector moreover being formed for the connection of at least one piece of downhole equipment, a downhole tool etc., e.g. a drill bit, a drive engine for same, a measuring instrument etc. to carry out drilling, downhole operations or measuring, which connector comprises connectable parts for the connecting and securing of the pipe end portion, including an inner adapter sleeve and an outer adapter and connector sleeve, which can be connected to the connecting element of an end piece/connecting piece.
Also, the invention relates to a method of establishing the connection and securing the pipe end portion to the connector.
2. Description of the Related Art
For connecting pieces for coiled tubing it is important, for space reasons, to allow the external diameter to be kept as small as possible, and it is also important that the connecting piece can stand high tensile loads, high pressure loads and the effect of high torques.
Existing connectors of this kind normally comprise an adapter sleeve with an externally conical smooth surface. Such an adapter sleeve with a smooth surface will cause a great expansive force on an external adapter and connector sleeve surrounding the adapter sleeve, when the connector is subjected to tensile load. This disadvantageous condition is normally compensated for by increasing the external diameter of the connector, which is also unfortunate and disadvantageous.
A smooth conical adapter sleeve bearing against the surrounding end portion of coiled tubing, can only absorb a highly limited torque.
Existing connectors are generally locked by set screws meant to have the task of absorbing torques. This is a particularly unfortunate construction as such screws are generally unsuitable for such a task, and may, at worst, come loose through vibrations, and may fall out, after which the loose set screws may cause damage to the well and downhole equipment.
Therefore, there is a need for a connector and method of connection to remedy or reduce, to a substantial degree, by simple means the drawbacks, disadvantages and limitations of use of conventional connectors of this kind and of other known connectors of similar types, and thus provide a connector for the purposes in question, in which the external diameter is kept as small as possible, and which exhibits, with dimensions corresponding to those of known connectors, a higher tensile end compressive strength and greater resistance towards external torques applied thereto.